Rogers' Rangers was initially a provincial company from the colony of New Hampshire, attached to the British Army during the Seven Years' War (called the French and Indian War in the United States). The unit was quickly adopted into the British army as an independent ranger company. It was trained by Major Robert Rogers as a rapidly deployable light infantry force tasked mainly with reconnaissance as well as conducting special operations against distant targets. Their tactics, built on earlier colonial precedents, but codified for the first time by Rogers, proved remarkably effective, so much so that the initial company was expanded into a ranging corps of more than a dozen companies (containing as many as 1,200–1,400 men at its peak). The ranger corps became the chief scouting arm of British Crown forces by the late 1750s. The British valued them highly for gathering intelligence about the enemy.